1. Technical Field
The present disclosure relates to trials for prosthetic implants, and more particularly, to providing articulating trials which are adjustable in situ to allow selection and positioning of a prosthetic joint which provides functionally correct motion similar to kinematic motion of a normal, non-prosthetic joint.
2. The Relevant Technology
One attribute of normal knee flexion is that, as the knee flexes, the contact points of the femur on the tibia move posteriorly. This posterior movement of the contact points is known as rollback. Also, normal knee rollback is much more pronounced on the lateral side of the knee than the medial side, which results in femoral external rotation during knee flexion.
Other prosthetic knees currently on the market do not use two separate fully guided motion paths, and as a consequence may not reproduce normal knee kinematics and need to use wear components made of polyethylene, or similar material, to accommodate the less-guided sliding that occurs during knee flexion. These existing methods and procedures may not be as effective as desired. There is a need to have a tibial insert of a prosthetic knee roll back on a medial pivot axis causing greater rollback on the lateral side than the medial side, like a normal, non-prosthetic knee.
Trials are used during an implantation procedure to simulate the prosthetic device to be implanted, allowing for selection of a proper prosthetic. In joint replacement procedures, there is a need for an articulating trial which simulates the articulation of the natural joint to allow more accurate selection of a properly sized and configured prosthetic. There is also a need for a guiding assembly that is adjustable in situ to precisely position the articulating trial and provide guidance for placement of the prosthetic device.